A system for thermally processing solid fuel to produce pyrolysis gases, syngas, tar, char, and/or torrefied products, which includes a bulk solids pump having a curved passage to move a feedstock therein and wherein the pump includes a spool supported for rotational movement. A sleeve shaped chamber or chambers surround all or a portion of at least an axial extent of said curved passage to permit containment of heated gases to heat solid fuel within the curved passage to thermally process the feedstock within the pump.